In this year’s data visualization presentation, he shared ideas from preeminent thought leader, Edward Tufte, and his seminal book, The Visual Display of Quantitative Information. Another thought leader Marshall highlighted was Stephen Few, who wrote several books on data presentation, including Show Me the Numbers.

When presenting, your focus should be on just showing the data. Don’t clutter it with extraneous visual information. Why does this matter? Your data is important. It helps you and those with whom you share this data better understand problems and make decisions. The goal for an excellent graph or chart should be to get the viewers of this data to ask questions.

Marshall showed the same information presented in both a cluttered and clean presentation. The first view might prompt more thoughts about mad scientists than about the rise and fall of U.S. patents over time. Presentation viewers are more likely to engage in a conversation about the data with the simple uncluttered presentation.

One of Tufte’s ideas Marshall shared was the data-to-ink ratio. This is the amount of ink devoted to the data compared to the total ink used in the graphic. For a PowerPoint presentation, think pixels instead of ink. The higher the ratio, the more you’re focusing the visual display on the data.

Marshall described “chartjunk” as additional graphics not related to the data in a quest to make the chart more aesthetically pleasing. Instead, it distracts from the data. If you think your graph is boring, you’re showing the wrong data. Open a USA Today newspaper and you’ll find examples of chartjunk–like a gas price tracker that shows a gas pump graphic with a window containing the average price and another containing the directional price change. Although cute, the data-to-ink ratio is low.

Another example Marshall shared is the comparison between the main Yahoo page and Google page. They are at opposite ends of the visual display spectrum.

For those that love the visually exciting, 3D graphics in Microsoft Office products like Word, Excel, and PowerPoint, Marshall’s simple message is, “Don’t use 3D.” Although it may look cool, the 3rd dimension does not add anything. When the graph has multiple data series, 3D makes it difficult to compare data between two data points. In 2D, comparisons are easier to make. Again, the focus shifts from the “eye candy” to the data itself.

You can also fall into the trap of distorting the data. The concept of “lie factor” is the size of the effect shown in the graphic divided by the size the effect in the data itself. Graphic treatments that show a 3D-perspective can visually distort the data. Bar charts often convey size, relative differences, and area better than pie charts do.

5 comments

You’ve highlighted some great concepts. Tufte’s book and presentations are highly recommended, and the importance of clean, unbiased visualization cannot be overstated. Combining these concepts along with key performance indicators can dramatically improve plant operations and prevent abnormal situations.
We continue to add technology to the plant, but simply “seeing” what the plant, unit, or device is doing is the cheapest and one of the most effective ways to fix things. Not only that, but the right graph can go a long way towards getting the right projects implemented at the right time.
I found Tufte’s ideas to be especially enlightening in his analysis of the Space Shuttle Challenger disaster. In his book Visual Explanations, he argues that better data visualization would have prevented the tragedy (excerpt here: http://www.asktog.com/books/challengerExerpt.html ). After seeing that, I was sold on the power of data visualization.

Looking forward to DeltaV 10’s operator graphic subsystem, I really hope that it fixes some of the data-ink clutter and other visualization problems with the existing iFix setup.
A case in point are the default dynamos for valves and tanks, that take up lots of screen space, have lots of fancy graphic details, and yet show just one data point (a level or valve position, for example)
After-market display design companies like Acuite have done some pretty effective things with DeltaV, but it’s taken a lot of work!

If you get the chance, I highly recommend his 1-day course. It’s well worth the money, and you get all 4 books included in the course fee.
See http://www.edwardtufte.com/tufte/courses for more information.